In this article, we’re going to discuss the different causes of spots of white on tomato leaves and other plant parts. Also, we’ll look at the damage they do and how to fix it naturally.
Tomatoes are grown nearly everywhere in the world in gardens and greenhouses. Like any plant, they are susceptible to impairments, with most of this being evident by the appearance of spots, patches, or specks on the fruit, stem, and/or leaves.
However, in some cases, you cannot get rid of the problem. This is due to the extent of the damage being too much for the plant to survive or the cause of the damage itself.
Below are some common causes of tomato plant leaves, fruit skin, and other parts turning white. We’ll also look at how to treat the problem naturally.
Pest Activity
Stink bugs feeding is one reason for cloudy spots or whitish areas on the leaves and fruits of tomato plants. Still, other garden pests such as aphids, thrips, and spider mites can also cause this kind of damage.
Leaves sustain the most damage from these pests. You may also notice cloudy white spots under the skin or inside your tomatoes.
However, you can prevent or deal with stink bug infestations relatively easily.
Treatment (Home Remedies):
- Handpicking
- Neem oil
- Insecticidal soap.
- Water hose.
Prevention:
- Weed control.
- Companion plants.
Adverse Weather Conditions
Sunscald is caused by a plant getting too much sun and/or being in the path of hot, dry wind. Therefore, hot weather or extreme heat are the main culprits.
With this condition, unripe or ripening fruits start showing pale white or yellowish blotches. However, sunscald is something that you can prevent relatively easily.
Treatment:
- Removal of damaged fruits.
- Organic sprays like IV Organic.
Prevention:
- Pruning
- Mulch
- Shade
- Evening watering
- Avoiding overhead watering
Nutrient Deficiencies
The kind of soil your plant is put into plays a big part in its health. While issues regarding nutrients are not as common as the first two subheads, they do happen.
Plants lacking certain nutrients may show whitening or yellowing of the leaves. The plant nutrients that are most affected include:
- Nitrogen: the addition of fertilizers such as bat guano can help correct nitrogen deficiency.
- Phosphorus: treatable with proper fertilizers, such as alfalfa meal.
- Potassium: adding kelp will help with this.
- Calcium: adding lime is one way to increase this nutrient.
- Manganese: apply a foliar feed containing manganese.
Disease
This category is another common cause or medium for tiny white spots on tomato plant leaves.
Plant diseases are caused by a wide range of conditions, including high humidity, poor drainage, and poor air circulation. Additionally, lack of sun, cooler temperatures, and excessive watering can also be factors.
1. Septoria Leaf Spot
Septoria leaf spot first appears on the lower leaves of the plant. You may notice circular gray spots with dark borders.
Treatment:
- Use of organic fungicides.
- Handpicking damaged leaves.
Prevention:
- Crop rotation.
- Leaf debris disposal to keep the disease from overwintering.
2. Powdery Mildew
If you notice your tomato leaves turning white, it is most likely powdery mildew. This common disease appears like a thin layer of powder on the leaves [1].
Treatment:
- Removing the dead leaves.
- Clearing leaf debris.
- Vinegar.
- Neem oil.
- Baking soda spray.
- Liquid soap.
- Organic copper fungicides such as Cueva.
Prevention:
- Watering late in the day.
- Improving drainage.
- Providing access to plenty of sunlight.
Read more on how to get rid of powdery mildew on plants.
3. Leaf Mold
Tomato leaf mold mostly affects plants growing inside greenhouses as well as those in high tunnels.
Symptoms may include faint green spots on the upper side of the leaves. You may also notice small gray, yellow, or white specks.
It is caused by the fungus Passalora fulva [2]. In severe cases, it can also affect the blossoms and fruits.
Treatment:
- Prune where needed.
- Remove leaf debris.
- Application of organic fungicides.
- Cleaning with a commercial sanitizer at the end of the growing season.
Prevention:
- Improving air circulation.
- Lowering humidity to below 85%.
- Use drip irrigation to avoid overhead watering.
4. Sclerotinia Stem Rot (White Mold)
You will notice this around the time of flowering. White mold mostly affects plants in wet and cold climates.
Tomato stems will look white with black pebble-like structures inside. Flowers may also have water-soaked areas.
Treatment:
- Remove all infected plants in severe cases.
- Prune leaves and lateral stems that are infected.
- Use a biofungicide.
Prevention:
- Plant in containers with fresh soil.
- Keep tools and hands clean.
- Provide good drainage.
- Use drip irrigation to avoid overhead watering.
- Sterilize infected soil during the summer months using sheeting over the ground. Also, let the sun raise the temperature of the soil to kill spores and mold in it.
5. Mosaic Rot
This is a viral disease that not only diminishes both the yield and the quality of the fruit but can also kill the plants.
Spots on leaves may appear yellow-green or faintly white.
Treatment:
- Removal of all infected plants—they can’t be saved.
- Boiling tools before washing with a strong detergent to avoid spreading disease.
- Washing hands to avoid spreading disease.
Prevention:
- Avoid gardening in wet conditions.
- Crop rotation using crops not susceptible to the virus.
Recommendations
As soon as the blemishes appear, action must be taken immediately, or else the entire crop can be devastated. Therefore, pick any treatment or home remedy for white spots on tomato leaves from the list above.
Even the simple act of handpicking the leaves will help with controlling the damage. Moreover, prevention begins with how you set up your garden, the condition of the soil, and adequate drainage.
If starting with seedlings, proper transitioning from indoors to outdoors is of utmost importance.
See our complete list of tomato diseases (with pictures) and how to treat them naturally.
Takeaway
These are just a few of the causes of white spots on your tomato plant’s leaves, stems, blossoms, and fruits. Some of them can be devastating to the crop. Besides, the last one, Mosaic Rot, can even spread to other plants as well.
However, despite all the things that can go wrong, tomato plants go well with other companions and are relatively easy to grow.
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